Share-Based Compensation (Additional Information Option Outstanding) (Details) (USD $)			12 Months Ended
	Dec. 31, 2011 Years	Dec. 31, 2010 Years	Dec. 31, 2011 $0 - $14 [Member] Years	Dec. 31, 2011 $14 - $28 [Member] Years	Dec. 31, 2011 $28 - $42 [Member] Years	Dec. 31, 2011 $42 - $56 [Member] Years	Dec. 31, 2011 $56 - $70 [Member] Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding	1,553,400	1,458,000	128,400	851,200	700	304,000	269,100
Weighted Average Exercise Price	$ 32.92	$ 29.73	$ 10.88	$ 21.76	$ 31.98	$ 45.05	$ 65.05
Weighted Average Remaining Contractual Life	6.8	6.9	2.7	7.2	4.3	8.0	6.0
Options Exercisable	958,000		128,400	477,700	700	82,000	269,100
Weighted Average Exercise Price	$ 34.58		$ 10.88	$ 20.96	$ 31.98	$ 50.94	$ 65.05
Exercise price range, lower range limit			$ 0	$ 14	$ 28	$ 42	$ 56
Exercise price range, upper range limit			$ 14	$ 28	$ 42	$ 56	$ 70